Flow deflector for a discharge valve system, discharge valve system and turbomachine comprising such a discharge valve system

ABSTRACT

The disclosure relates to a flow deflector for a discharge valve system of a double flow turbomachine compressor. The flow deflector comprises a wall provided with a plurality of ejection channels positioned to discharge a discharge air flow. The ejection channels are arranged in rows along aligned directions, substantially parallel to an axial plane of the deflector. The ejection channels of each row are oriented at a defined angle between a normal line to the wall and axes of the ejection channels, and decreasing between an upstream edge and a downstream edge of the wall, as defined according to the direction of movement of the air flow.

FIELD OF THE INVENTION

The present invention relates to the field of turbomachine, inparticular to double flow turbomachine for aircraft. It relates inparticular to a discharge valve system making it possible to discharge aportion of the air flow passing through a compressor in a flowpath ofthe turbomachine. It also relates to a turbomachine comprising such adischarge valve system.

STATE OF THE ART

A double flow turbomachine generally comprises, from upstream todownstream, according to the direction of the gas flow inside theturbomachine, at least one compressor, a combustion chamber and aturbine forming a gas generator installed in an inner casing. A mobilefan is arranged upstream from the gas generator and inside an outercasing, which also comprises the inner casing. The air passing throughthe turbomachine is split into a primary flow, or hot air flowcirculating inside the gas generator, and a secondary flow, or cold airflow circulating around the inner casing. The hot air flow is compressedby the compressor stages of the turbomachine before entering thecombustion chamber. The combustion energy is recovered by the turbinestages that contribute to driving the compressor stages and the upstreammobile fan, and therefore to providing the thrust of the turbomachine.The cold flow also participates in providing the thrust of theturbomachine.

Turbomachines are also provided with one or more discharge valvesystems, also known by the term “Handling Bleed Valve” (HBV), that makeit possible for the recovery of part of the hot air flow compressed bythe compressor and, in particular, by a high-pressure compressor, beforedischarging it in the cold air flow, with which it is mixed. The purposeof this discharge is to stabilise the operations of the compressor bylimiting surge, rotating stall or flotter phenomena.

Documents US-A1-2010/199633, US-A1-2009/188257, EP-A1-2891769 andEP-A2-2062688 disclose various types of discharge valve systemscomprising a flow deflector provided with a plurality of openingsoriented in the same direction. These openings discharge the flow of hotair from the compressor, either in the direction of circulation of thecold air flow, or in the opposite direction of the cold air flowcirculation. These arrangements make it possible to increase theincorporation of the hot air flow discharged into the cold air flow, tolimit thermal stresses on nearby structures and/or components that havenot been configured to withstand high temperatures.

However, these arrangements do not consider or have solutions that makeit possible to limit the perturbations in the circulation of the coldair flow generated by the fan which travels up the operating line of thefan in a compression-flow field and impacts the functioning of theturbomachine.

Aim of the Invention

The present applicant has therefore provided, as an aim, a flowdeflector of a compressor discharge valve system that makes it possibleto limit the perturbation caused by the circulation of the cold airflow, while limiting the thermal stresses exerted on the environment ofthe flowpath wherein an air flow circulates.

Presentation of the Invention

This aim is achieved according to the invention with a flow deflector ofa compressor discharge valve system of a double flow turbomachine, theflow deflector being arranged at least in part in a flowpath in whichcirculates an air flow and comprising a wall provided with a pluralityof ejection channels capable of discharging a discharge air flow fromthe compressor in the flowpath of the turbomachine, the ejectionchannels being arranged in rows along aligned directions that aresubstantially parallel to an axial plane of the deflector, the ejectionchannels of each row being oriented at an angle defined between a normalline to the wall and the axes of the ejection channels, and decreasingbetween an upstream edge and a downstream edge of the wall defined alongthe direction of movement of the air flow, and at least the channels ofat least one row situated in the proximity of the upstream edge beingoriented such that the discharge flow is substantially flush with thewall of the deflector and along the movement direction of the air flow.

In particular, each angle varies by decreasing along the first directionof movement of the air flow.

According to one characteristic of the invention, at least one rowlocated in the proximity of the downstream edge is provided withchannels that are oriented so that the discharge flow is substantiallyparallel to the central axis of the deflector. In other words, thedischarge air flow passing through the ejection channels is guided in adirection that is substantially transversal in the direction of thedownstream flow direction.

This flow deflector resolves the abovementioned disadvantages. Indeed,this flow deflector makes it possible to discharge the discharge airflow of the compressor in a direction that is flush and almost barelymissthe wall of the deflector in the upstream portion, so as not todisrupt the circulation of the air flow coming from the fan of theturbomachine. The downstream rows make it possible to discharge adischarge air flow along a direction that is almost vertical in order,on the one hand, to not burn the structures and/or components near thesecondary flowpath, and on the other hand, to create a “fluid wall” thatprevents the air flow coming from the fan from flattening the dischargeair flow downstream from the fan against the walls of the secondaryflowpath, wherein circulates the air flow of the fan.

According to one characteristic of the invention, the angle of thechannels varies between 65° and 5°, between the upstream edge and thedownstream edge. Therefore, the angles decrease progressively and thedischarge air flow has a progressive straightening that is integrated inthe air flow coming from the fan in the secondary flowpath withoutnegatively impacting the performance of the fan, while also protectingthe walls of the secondary flowpath from thermal stresses.

According to one characteristic of the invention, the ejection channelsof each row are oriented at the same angle.

According to one characteristic of the invention, each ejection channelis oriented at an angle of between 10° and 60°.

According the one characteristic of the invention, each ejection channelhas a constant circular section.

According to one characteristic of the invention, the wall of the flowdeflector has a spherical shape.

In an advantageous but non-limiting manner, each ejection channelextends on either side of the wall and has a constant circular sectionso as to facilitate the manufacturing of the flow deflector and to makeit possible for the three-dimensional arrangement of the channels in thewall.

According to another characteristic of the invention, the flow deflectorcomprises a cylindrical body, preferably but in a non-limiting manner,with a circular section, coupled to an air inlet and to the wallprovided with ejection channels, the body defining a passage between theair inlet and the flow deflector.

In an advantageous but non-limiting manner, the number of rows ofejection channels is between 20 and 30.

In particular, the ejection channels occupy almost all of the surface ofthe wall of the flow detector.

According to another characteristic of the invention, the wall of theflow deflector comprises at least one first series of rows positionedupstream and of which the channel angles of two consecutive rows areidentical and between 55° and 65°, and one second series of rowspositioned downstream and comprising at least one row of channels, theangles of which are between 5° and 15°.

According also to another characteristic of the invention, the wallcomprises an intermediate series of rows located between the firstseries and the second series, the angles of the channels of the rows ofthis intermediate series varying by an identical value between each row,such that the variation of the angles is progressive and linear.

In an advantageous but non-limiting manner, the angles of the channelsof the rows of the intermediate series are between 3° and 8°.

The invention also relates to a discharge valve system of a double flowturbomachine, the system comprising:

-   -   a flow deflector having any one of the abovementioned        characteristics,    -   a duct connected to the flow deflector and comprising a hot air        inlet,    -   a regulation device, making it possible to regulate the passage        of the discharge air flow between the hot air inlet of the duct        and the flow deflector, and    -   an actuator acting on the regulation device such that the device        occupies at least one first position wherein the hot air inlet        is closed and a second position wherein the hot air inlet is        released or open.

According to one characteristic of the invention, the regulation devicecan occupy an intermediate position between the first position and thesecond position.

The invention also relates to a double flow turbomachine comprising aprimary flowpath wherein circulates a hot air flow and a secondaryflowpath wherein circulates a cold air flow, the flowpaths beingseparated by an inter-flowpath casing, at least one discharge valvesystem having any one of the abovementioned characteristics beingarranged in the inter-flowpath casing. Thus, the discharge flow passingthrough the ejection channels is guided along at least one directionoriented along the direction of air flow circulation, and along adirection that is substantially perpendicular to the direction of airflow circulation. The orientation of each channel is formed of a radialcomponent and an axial component, but generally, can comprise a reducedand constant tangential component or a component making it possible fora slight divergence of the discharge flow (5 to 10 degrees).

BRIEF DESCRIPTION OF THE FIGURES

The invention will be better understood, and other aims, details,characteristics and advantages of it will become clearer upon readingthe following detailed explanatory description relating to theembodiments of the invention, provided as examples and not limitedthereto, and with reference to the appended figures, wherein:

FIG. 1 shows an axial and partial cross-sectional view of an example ofa turbomachine to which the invention applies;

FIG. 2 is a schematic and axial cross-sectional view of a flowpath,wherein is positioned a flow deflector according to the invention;

FIG. 3 shows a discharge valve system comprising a regulation device andan actuator acting on the regulation device;

FIG. 4 is a perspective view of an example of a flow deflector accordingto the invention;

FIG. 5 is a top view of the flow deflector shown in FIG. 4;

FIG. 6 is a schematic and cross-sectional view of the flow deflectorshown in FIG. 5; and

FIG. 7 is a cross-sectional and detailed view of a wall of the flowdeflector according to the invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 schematically shows a turbomachine of an aircraft according tothe invention. In particular, it shows a double flow turbomachine thatextends along an axis X. This turbomachine 100 generally comprises anouter casing 101 surrounding a gas generator 102, upstream from which ismounted a fan 103. In the present invention and generally, the terms“upstream” and “downstream” are defined with respect to the circulationof gases in the turbomachine 100. The terms “up” and “down” are definedwith respect to a radial axis perpendicular to the axis X.

The gas generator 102 comprises, in this example, from upstream todownstream, a low-pressure compressor, a high-pressure compressor, acombustion chamber, a high-pressure turbine and a low-pressure turbine.The generator is housed in an inner casing 104.

The fan 103 here is ducted and comprises a shroud 50 secured to theouter casing 101 and surrounding a plurality of mobile vanes of the fan51, which are mounted and extend radially from a fan shaft connected toa drive shaft of the gas generator 102.

The fan 103 compresses the air coming into the turbomachine 100, whereit is split into a hot air flow circulating in a primary flowpath V1which passes through the gas generator, and a cold air flow circulatingin a secondary flowpath V2 around the gas generator 102. In particular,the primary flowpath V1 and the secondary flowpath V2 are separated byan annular inter-flowpath casing 105 arranged between the outer casing101 and the inner casing 104. The flow circulating in the primaryflowpath V1 is conventionally compressed by the compressor stages beforeentering the combustion chamber. The combustion energy is recovered bythe turbine stages which ensure the driving of the compressor stages andthe fan. The cold air flow F circulating in the secondary flowpath V2 isoriented along an axial direction, substantially parallel to thelongitudinal axis X, and itself contributes to providing thrust to theturbomachine 100.

In reference to FIGS. 2 and 3, a discharge valve system 1 is arrangedbetween the primary flowpath V1 and the secondary flowpath V2 of theturbomachine 100. The discharge valve system 1 is mounted on a wall 12of the inter-flowpath casing 105 and right side up the high-pressurecompressor. Therefore, the hot air collected for discharging thehigh-pressure compressor is ejected into the secondary flowpath V2. Thedischarge valve system 1 comprises a flow deflector 4, an air regulationdevice 16, an actuator 15 acting on the regulation device 16 and a duct17.

The flow deflector 4 comprises a body 2 coupled to an air inlet 3 andextending from a wall 5. The body 2 has a generally cylindrical shapewith a circular section and a revolution axis R (FIG. 6). The flowdeflector 4 comprises a collar 14 secured to the body 2 and surroundingthe air inlet 3. This collar 14 makes it possible to secure the flowdeflector 4 to the duct 17 in the inter-flowpath casing 105. The flowdeflector 4 is intended to be arranged in the secondary flowpath V2 suchthat the hot air flow received from the compressor through the air inlet3 is ejected directly into the secondary flowpath V2 through ejectionchannels. The ejection channels are situated in the secondary flowpath.The body 2 defines a passage for the air flow between the air inlet 3and the ejection channels.

The flow deflector 4 is connected to the duct 17 that extends throughthe inter-flowpath casing 105. For this, the collar 14 comprises holespassing through the wall of the latter, on either side thereof. Theholes are intended to receive removable attachment means, such asscrews. The duct 17 comprises a hot air inlet (not shown) intended tofluidly communicate with the primary flowpath V1 and to receive aportion of the hot flow coming from the high-pressure compressor. Theduct 17 also comprises a hot air outlet coupled to the air inlet 3 ofthe flow deflector 4. The duct 17 makes it possible for the passage ofthe hot air flow from the compressor towards the flow deflector 4.

The regulation device 16 and the actuator 15 are arranged inside theduct 17. The device 16 makes it possible to regulate the hot airdischarge air flow coming from the compressor. The device 16 comprises aneedle valve movable along a radial axis substantially perpendicular tothe axis X. The needle valve moves from a first position wherein the hotair coming from the compressor does not circulate from the hot air inletof the duct 17 towards the flow deflector and a second position whereinthe hot air coming from the compressor circulates from the hot air inletof the duct 17 towards the flow deflector. The first positioncorresponds to a position wherein the hot air inlet of the compressor isclosed and the second position corresponds to a position wherein the hotair inlet is open. The movement of the needle valve is controlled by theactuator 15. In particular, when it is necessary to discharge hot airfrom the compressor into the secondary flowpath V2, the actuator 15causes the upwards movement of the needle valve in order to open the hotair inlet. The flow of hot air coming from the compressor thus travelsthrough the duct 17 towards the flow deflector 4. A discharge air flowFc is then discharged in the flowpath V2 through the ejection channelsdescribed below.

In reference to FIGS. 4 to 7, the flow deflector comprises a wall 5provided with a plurality of ejection channels 6 capable of dischargingthe hot air flow coming from the compressor into the secondary flowpathV2, wherein circulates the cold air flow F. The ejection channels 6 areconfigured to eject a discharge air flow Fc that does not come intodirect contact with the walls 12, 13 of the secondary flowpath V2 anddoes not disrupt the flow and circulation of the cold air flow. In otherwords, the discharge air flow Fc is not ejected so as to counter thedirection of air flow coming from the fan. The wall 5 of the deflectorhas an arched shape. The thickness thereof is constant. The wall has aconstant thickness of between 1 and 5 mm. In particular, the wall has afirst concave internal surface 7 rotated towards the regulation device16 of the discharge valve system 1 and a second convex external surface8 opposite the first internal surface and rotated towards the secondaryflowpath V2. The wall 5 here has a spherical shape. It has a circularperipheral edge. Of course, the peripheral edge of the wall, and thewall itself, can be of another shape, such as a rectangular shape.

In reference to FIG. 7, the ejection channels 6 are formed in the wall 5and extend on either side of the latter between the first surface 7 andthe second surface 8. The ejection channels 6 have, here, a constantcircular section about a central axis C. The diameters of the ejectionchannels distributed on the wall 5 are here also identical. In theexamples shown, the ejection channels 6 occupy almost all of the surfaceof the wall 5. Each ejection channel 6 has an inlet orifice 10 definedin the first surface 7 and fluidly communicating with the passage of thebody 2 and an outlet orifice 11 defined in the second surface 8 andfluidly communicating with the secondary flowpath V2.

Each ejection channel 6 is oriented at an angle a defined between thecentral axis C and a normal line D to the wall 5 of the deflector.

According to one characteristic of the invention, the angles of theejection channels 6 vary by decreasing between an upstream edge and adownstream edge of the wall defined along the direction of movement ofthe air flow of the fan.

Each angle α is between 10° and 60°.

In an advantageous but non-limiting manner, the ejection channels 6 arearranged in several rows 9 along aligned directions A (see FIG. 5). Therounded shape of the aligned direction seen in FIGS. 4 and 5 is due tothe spherical shape of the wall 5. The aligned directions aresubstantially parallel to an axial plane S of the wall 5 intersectingwith the revolution axis R of the body. This axial plane S issubstantially perpendicular to the direction of the movement of the fanair flow. The number of rows 9 of ejection channels is between 20 and30. In the example shown, the wall 5 of the flow deflector 4 comprises24 rows of ejection channels, each forming a discharge flow blade. Eachrow 9 comprises between 4 and 50 ejection channels 6. It is understood,that the number of rows and the number of ejection channels per rowdepends on the dimensions of the flow deflector, on the dimensions ofthe ejection channels and on the required flow through the diffuser whenthe valve is open.

According to one characteristic of the invention, the ejection channelsof each row are oriented at the same angle a so as to form a dischargeair flow blade Fc. As is shown in FIG. 7, the angle of the rows ofejection channels 6 varies between 65° and 5° from upstream todownstream with respect to the direction of movement of the air flow F,when the discharge valve system 1 is installed in the turbomachine 100.In particular, this variation is defined between an upstream edge and adownstream edge of the wall 5 with respect to the axial plane S.Therefore, the discharge air flow Fc blades passing through the ejectionchannels 6 are guided along a direction oriented in the direction ofcold flow circulation in the upstream section and along a direction thatis substantially transversal with respect to the direction of cold flowcirculation in the downstream section. At least one row located in theproximity of the upstream edge is provided with channels oriented suchthat the discharge flow Fc is substantially flush with and tangential tothe wall of the deflector according to the direction of movement of theair flow (F) of the fan. Likewise, at least one row located in theproximity of the downstream edge is provided with channels oriented suchthat the discharge flow is substantially parallel to the central axis Rof the deflector.

In reference to FIG. 6, the rows 9 comprise a first series S1 of rowspositioned upstream, and of which the angles of the channels of twoconsecutive rows are identical. In this example, the first series S1 isarranged upstream from the axial plane S, wherein the rows 9 areoriented at the same angle. In an advantageous but non-limiting manner,the angle of the ejection channels of this first series S1 is of 60°,such that the blades of the discharge air flow Fc are substantiallytangential to the wall 5 of the deflector and do not disrupt thecirculation of the cold air flow F. Moreover, the fact that the flowsare tangential to the wall of the deflector prevent them from cominginto direct contact with the walls of the secondary flowpath, and inparticular, the inner wall 13 of the outer casing 101. Downstream fromthis first series S1 of rows, a second series S2 of rows is provided,wherein the angle of the channels of at least one row 9 is oriented atan angle a between 5° and 15°, such that the flow is substantiallyvertical, to avoid burning the walls of the secondary flowpath, and inparticular the inner wall 12 of the inter- flowpath casing 105. In thisexample, the angle of the channels of this second series S2 is 10°. Anintermediate series SI of rows is arranged between the first series ofrows S1 and the second series of rows S2. In this intermediate series SIof rows, the orientation angle a of the channels of the rows varies ateach consecutive row by between 3° and 8°. In other words, twoconsecutive rows of ejection channels have angles that vary by 3° to 8°.

Each series has a given number of rows 9. In a preferred butnon-limiting manner, the first and second series S1, S2 comprise asubstantially identical number of rows 9. The intermediate series SIcomprises twice as many rows 9 as either of the first and second series.In other words, the number of rows of the intermediate series is greaterthan the number of rows of the first series. Similarly, the number ofrows of the intermediate series is greater than the number of rows ofthe second series. This enables a linear progression of the discharge ofthe discharge air flow into the discharge passage.

Thus, when the discharge air flow is ejected into the secondary flowpathV2, it is oriented along several blades, of which a first series ofdischarge air flow blades is substantially tangential to the wall 5 ofthe flow deflector, an intermediate series of discharge air flow bladesand a second series of discharge air flow blades that are substantiallyvertical. The first series of air flow blades circulating in the centreof the passage substantially axially and coming into contact with thesecond series of blades changes the vertical direction of the air flowblades of the second series such that they also circulate in the centreof the flowpath V2 and at a distance of the walls 12, 13. The cold aircirculation and flow F is not disrupted.

1. A flow deflector of a discharge valve system of a compressor of adouble flow turbomachine, the flow deflector being arranged at least inpart in a flowpath of the turbomachine in which circulates an air flowand comprising a wall provided with a plurality of ejection channelspositioned to discharge a discharge air flow from the compressor in theflowpath of the turbomachine, the ejection channels being arranged inrows along aligned directions that are substantially parallel to anaxial plane of the deflector, the ejection channels of each row beingoriented at an angle defined between a normal line to the wall and axesof the ejection channels, wherein the ejection channels vary bydecreasing from an upstream edge to a downstream edge of the walldefined along a direction of movement of the air flow and wherein atleast the ejection channels of at least one row situated in a proximityof the upstream edge are oriented such that a discharge flow issubstantially flush with the wall of the deflector and along thedirection of movement of the air flow.
 2. The flow deflector accordingto claim 1, wherein at least one row of the ejection channels located ina proximity of the downstream edge is provided with channels orientedsuch that the discharge flow is substantially parallel to a central axisof the deflector.
 3. The flow deflector according to claim 1, whereinthe angle of the channels varies from 65° to 5° between the upstreamedge and the downstream edge.
 4. The flow deflector according to claim1, wherein the ejection channels of each row are oriented at the sameangle.
 5. The flow deflector according to claim 1, wherein each ejectionchannel has a constant circular section.
 6. The flow deflector accordingto claim 1, wherein the wall has a spherical shape.
 7. The flowdeflector according to claim 1, wherein a number of rows of ejectionchannels is between 20 and
 30. 8. The flow deflector according to claim1, wherein the wall of the flow deflector comprises at least one firstseries of rows positioned upstream and of which the channel angles oftwo consecutive rows are identical and are between 55° and 65°, and asecond series of rows positioned downstream and comprising at least onerow of channels, the angles of which are between 5° and 15°.
 9. The flowdeflector according to claim 8, wherein the wall comprises anintermediate series of rows between the first series and the secondseries, wherein angles of the channels of the rows of the intermediateseries vary by an identical value between each row.
 10. The flowdeflector according to claim 9, wherein a variation of the angles of thechannels of the rows of the intermediate series is between 3° and 8°.11. The discharge valve system of the double flow turbomachine, thesystem comprising: the flow deflector according to claim 1; a ductconnected to the flow deflector and comprising a hot air inlet; aregulation device configured to regulate the passage of the dischargeair flow between the hot air inlet of the duct and the flow deflector;and an actuator acting on the regulation device, such that theregulation device occupies at least one first position wherein the hotair inlet is closed and one second position wherein the hot air inlet isopen.
 12. The double flow turbomachine comprising a primary flowpathcirculating a hot air flow and a secondary flowpath circulating a coldair flow, the primary and secondary flowpaths being separated by aninter-flowpath casing wherein, in the inter-flowpath casing, at leastone discharge valve system according to claim 11 is arranged.